Abstract

本論文では，3 次元コンピュータ・グラフィックスにおける逆遠近法を提案する．逆遠近法とは絵画における描画法の1 つであり，通常の透視投影法とは逆に遠くよりも近くの物体の方が画面上で小さく描かれることをいう．提案手法では，移動する視点から見た投影像をまとめることによって3 次元コンピュータ・グラフィックスにおける逆遠近法を実現している．また，逆遠近法で描かれた絵画によく見られるように，画面内に異なる投影法によって描かれた物体が混在する場合を想定している．そのため通常の透視投影法によって描画された画面内において，一部の物体のみを逆遠近法によって投影できる．しかも，対象物体に反射，透過・屈折による質感表現と影付けが可能であるという特徴を持つ．また，逆遠近法によって線遠近法による奥行き手がかりが崩れたとしても，投影像において有効な奥行き手がかりである物体の重なり，位置関係，大きさに関して，透視投影時の投影像の状態をほぼ保持することが可能である．We propose an algorithm of inverted perspective for 3-dimensional computer graphics. The inverted perspective is a technique for drawings and pictures. Objects near a viewpoint are drawn smaller than far objects. This characteristic is opposite to the ordinary perspective. The proposed algorithm draws 3-dimensional computer graphics using the inverted perspective by patching projected images from multi-viewpoints. The algorithm considers mixture of projective methods in an image plane. The mixture of projective methods is a popular usage of the inverted perspective on ordinary drawings and pictures. Therefore, the algorithm can draw only part of objects by the inverted perspective in an image projected by the ordinary perspective. Moreover, reflection, refraction for material representation, and shadowing can be used. In the inveted perspective, the liner perspective is broken, but the proposed algorithm can maintain three depth cues that are oclusions, positions, and size of objects in an image plane.

We propose an algorithm of inverted perspective for 3-dimensional computer graphics. The inverted perspective is a technique for drawings and pictures. Objects near a viewpoint are drawn smaller than far objects. This characteristic is opposite to the ordinary perspective. The proposed algorithm draws 3-dimensional computer graphics using the inverted perspective by patching projected images from multi-viewpoints. The algorithm considers mixture of projective methods in an image plane. The mixture of proiective methods is a popular usage of the inverted perspective on ordinary drawings and pictures. Therefore, the algorithm can draw only part of objects by the inverted perspective in an image projected by the ordinary perspective, Moreover, reflection, refraction for material representation, and shadowing can be used. In the inveted perspective, the liner perspective is broken, but the proposed algorithm can maintain three depth cues that are oclusions, positions, and size of objects in an qimage plane.